Liquid-crystal medium comprising polymerizable compounds

Abstract

A polymerizable compound having absorption in the long UV wavelength range, a liquid-crystal (LC) medium comprising the polymerizable compound, and the use of the compound or LC medium for optical, electro-optical and electronic purposes, in particular in LC displays, especially in LC displays of the PSA (polymer sustained alignment) or SA (self-aligning) mode, an LC display of the PSA or SA mode comprising the compound or LC medium, and a process of manufacturing the LC display.

The invention claimed is: 
     
         1 . A polymerizable compound of formula I1: 
       
         
           
           
               
               
           
         
         wherein the individual radicals, independently of each other and on each occurrence identically or differently, have the following meanings: 
         P denotes acrylate or methacrylate; 
         Sp denotes a single bond; 
         L denotes F, Cl, Br, —CN or straight chain alkyl having 1 to 25 C atoms or branched or cyclic alkyl having 3 to 25 C atoms, wherein one or more non-adjacent CH 2 -groups are optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —N(R 0 )—, —Si(R 0 R 00 )—, —CH═CH—, or —C≡C— in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by F or Cl; 
         R 0 , R 00  denote H or alkyl with 1 to 12 C atoms; and 
         r1 denotes 0, 1, 2, 3, or 4. 
       
     
     
         2 . The compound according to  claim 1 , wherein L is selected from F, CH 3 , OCH 3 , OC 2 H 5 , C 3 H 5 , CH═CH 2 , and C(CH 3 )═CH 2 . 
     
     
         3 . The compound according to  claim 1 , wherein the compound of formula I1 comprises one or more compounds selected from subformulae I1-1 to I1-18: 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
       
     
     
         4 . An LC medium comprising one or more compounds according to  claim 1 . 
     
     
         5 . The LC medium according to  claim 4 , further comprising one or more compounds of formula II: 
       
         
           
           
               
               
           
         
         wherein the individual radicals, independently of each other and on each occurrence identically or differently, have the following meanings: 
         R 1  and R 2  denote straight chain, cyclic alkyl having 1 to 25 C atoms or branched or cyclic alkyl having 3 to 25 C atoms, wherein one or more non-adjacent CH 2 -groups are optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, CR 0 ═CR 00 —, —C≡C—, 
       
       
         
           
           
               
               
           
         
       
       in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by F or Cl;
 A 1  and A 2  denote a group selected from the following formulae; 
 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         wherein the individual radicals, independently of each other and on each occurrence identically or differently, have the following meanings; 
         Z 1  and Z 2  denote —CH 2 CH 2 —, —CH═CH—, —CF 2 O—, —OCF 2 —, —CH 2 O—, —OCH 2 —, —CO—O—, —O—CO—, —C 2 F 4 —, —CF═CF—, —CH═CH—CH 2 O—, or a single bond; 
         L 1 , L 2 , L 3 , and L 4  
 denote F, Cl, OCF 3 , CF 3 , CH 3 , CH 2 F, or CHF 2 ; 
 
         Y denotes H, F, Cl, CF 3 , CHF 2 , or CH 3 ; 
         L c  denotes CH 3  or OCH 3 ; 
         a1 denotes 1 or 2; and 
         a2 denotes 0 or 1. 
       
     
     
         6 . The LC medium according to  claim 5 , further comprising one or more compounds of formula II selected from the group consisting of compounds of the formulae IIA, IIB, IIC, and IID: 
       
         
           
           
               
               
           
         
         in which 
         R 2A  and R 2B  
 each, independently of one another, denote H or an alkyl or alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3 , or at least monosubstituted by halogen, where, in addition, one or more CH 2  groups in these radicals are optionally replaced by —O—, —S—, 
 
       
       
         
           
           
               
               
           
         
       
       —C≡C—, —CF 2 O—, —OCF 2 —, —OC—O—, or —O—CO— in such a way that O atoms are not linked directly to one another;
 L 1  to L 4  each, independently of one another, denote F, Cl, CF 3 , or CHF 2 ; 
 Y denotes H, F, Cl, CF 3 , CHF 2 , or CH 3 ; 
 Z 2 , Z 2B , and Z 2D  
 each, independently of one another, denote a single bond, —CH 2 CH 2 —, —CH═CH—, —CF 2 O—, —OCF 2 —, —CH 2 O—, —OCH 2 —, —COO—, —OCO—, —C 2 F 4 —, —CF═CF—, or —CH═CHCH 2 O—; 
 
 p denotes 0, 1, or 2; and 
 q on each occurrence, identically or differently, denotes 0 or 1. 
 
     
     
         7 . The LC medium according to  claim 5 , further comprising one or more compounds of formula III: 
       
         
           
           
               
               
           
         
         in which 
         R 11  and R 12  
 each, independently of one another, denote H, or an alkyl or alkoxy radical having 1 to 15 C atoms, where one or more CH 2  groups in these radicals may each be replaced, independently of one another, by 
 
       
       
         
           
           
               
               
           
         
       
       —C≡C—, —CF 2 O—, —OCF 2 —, —CH═CH—, by —O—, —CO—O—, or —O—CO— in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms are optionally replaced by halogen;
 A 3  on each occurrence, independently of one another, denotes
 a) 1,4-cyclohexenylene or 1,4-cyclohexylene radical, in which one or two non-adjacent CH 2  groups are optionally replaced by —O— or —S—, 
 b) a 1,4-phenylene radical, in which one or two CH groups are optionally replaced by N, or 
 c) a radical selected from the group consisting of spiro[3.3] heptane-2,6-diyl, 1,4-bicyclo[2.2.2] octylene, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, phenanthrene-2,7-diyl, and fluorene-2,7-diyl, 
 wherein the radicals a), b), and c) are optionally mono- or polysubstituted by halogen atoms; 
 
 n denotes 0, 1, or 2; 
 Z 1  on each occurrence independently of one another denotes-CO—O—, —O—CO—, —CF 2 O—, —OCF 2 —, —CH 2 O—, —OCH 2 —, —CH 2 —, —CH 2 CH 2 —, —(CH 2 ) 4 —, —CH═CH—CH 2 O—, —C 2 F 4 —, —CH 2 CF 2 —, —CF 2 CH 2 —, —CF═CF—, —CH═CF—, —CF═CH—, —CH═CH—, —C≡C—, or a single bond; 
 L 11  and L 12  each, independently of one another, denote F, Cl, CF 3 , or CHF 2 ; and 
 W denotes O or S. 
 
     
     
         8 . The LC medium according to  claim 5 , further comprising one or more compounds of formula IV: 
       
         
           
           
               
               
           
         
         in which 
         R 41  denotes an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkenyl radical having 2 to 7 C atoms; and 
         R 42  denotes an unsubstituted alkyl radical having 1 to 7 C atoms, an unsubstituted alkoxy radical having 1 to 6 C atoms, or an unsubstituted alkenyl radical having 2 to 7 C atoms. 
       
     
     
         9 . The LC medium according to  claim 5 , further comprising one or more compounds of formula V: 
       
         
           
           
               
               
           
         
         in which 
         R 51  and R 52  
 independently of one another, denote an unsubstituted alkyl radical having 1 to 7 C atoms, an unsubstituted alkenyl radical having 2 to 7 C atoms, or an unsubstituted alkoxy radical having 1 to 6 C atoms; 
 
       
       
         
           
           
               
               
           
         
       
       identically or differently, denote 
       
         
           
           
               
               
           
         
         Z 51 —, Z 52  each, independently of one another, denote-CH 2 —CH 2 —, —CH 2 —O—, —CH═CH—, —C≡C—, —COO—, or a single bond; and 
         n is 1 or 2. 
       
     
     
         10 . The LC medium according to  claim 5 , further comprising one or more additives selected from the group consisting of stabilizers, chiral dopants, polymerization initiators, and self alignment additives. 
     
     
         11 . A process of preparing an LC medium, comprising the steps of mixing one or more polymerizable compounds comprising a compound of formula I1: 
       
         
           
           
               
               
           
         
         wherein the individual radicals, independently of each other and on each occurrence identically or differently, have the following meanings: 
         P denotes acrylate or methacrylate; 
         Sp denotes a single bond; 
         L denotes F, Cl, Br, —CN or straight chain alkyl having 1 to 25 C atoms or branched or cyclic alkyl having 3 to 25 C atoms, wherein one or more non-adjacent CH 2 -groups are optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —N(R 0 )—, —Si(R 0 R 00 )—, —CH═CH—, or —C≡C— in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by F or Cl; 
         R 0 , R 00  denote H or alkyl with 1 to 12 C atoms; and 
         r1 denotes 0, 1, 2, 3, or 4; 
       
       with one or more compounds of formula II: 
       
         
           
           
               
               
           
         
         wherein the individual radicals, independently of each other and on each occurrence identically or differently, have the following meanings: 
         R 1  and R 2  denote straight chain, alkyl having 1 to 25 C atoms or branched or cyclic alkyl having 3 to 25 C atoms, wherein one or more non-adjacent CH 2 -groups are optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, CR 0 ═CR 00 —, —C≡C—, 
       
       
         
           
           
               
               
           
         
       
       in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by F or Cl;
 A 1  and A 2  denote a group selected from the following formulae: 
 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         wherein the individual radicals, independently of each other and on each occurrence identically or differently, have the following meanings: 
         Z 1  and Z 2  denote —CH 2 CH 2 —, —CH═CH—, —CF 2 O—, —OCF 2 —, —CH 2 O—, —OCH 2 —, —CO—O—, —O—CO—, —C 2 F 4 —, —CF═CF—, —CH═CH—CH 2 O—, or a single bond, 
         L 1 , L 2 , L 3 , and L 4  
 denote F, Cl, OCF 3 , CF 3 , CH 3 , CH 2 F, or CHF 2 ; 
 
         Y denotes H, F, Cl, CF 3 , CHF 2 , or CH 3 ; 
         L C  denotes CH 3  or OCH 3 ; 
         a1 denotes 1 or 2; and, 
         a2 denotes 0 or 1; and 
       
       optionally with further liquid-crystalline compounds and/or additives; and 
       optionally polymerizing the polymerizable compounds. 
     
     
         12 . An LC display comprising an LC medium as defined in  claim 4 . 
     
     
         13 . The LC display according to  claim 12 , which is a PSA or SA display. 
     
     
         14 . The LC display according to  claim 13 , which is a PS-VA, PS-IPS, PS-FFS or SA-VA display. 
     
     
         15 . The LC display according to  claim 13 , comprising:
 two substrates, at least one of which is transparent to light;   an electrode provided on each substrate or two electrodes provided on only one of the substrates; and   located between the substrates a layer of an LC medium comprising one or more polymerizable compounds comprising:   i) a compound of formula I1:   
       
         
           
           
               
               
           
         
         wherein the individual radicals, independently of each other and on each occurrence identically or differently, have the following meanings: 
         P denotes acrylate or methacrylate; 
         Sp denotes a single bond; 
         L denotes F, Cl, Br, —CN or straight chain alkyl having 1 to 25 C atoms or branched or cyclic alkyl having 3 to 25 C atoms, wherein one or more non-adjacent CH 2 -groups are optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —N(R 0 )—, —Si(R 0 R 00 )—, —CH═CH—, or —C≡C— in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by F or Cl; 
         R 0 , R 00  denote H or alkyl with 1 to 12 C atoms; and 
         r1 denotes 0, 1, 2, 3, or 4; 
         and optionally ii) one or more compounds of formula II: 
       
       
         
           
           
               
               
           
         
         wherein the individual radicals, independently of each other and on each occurrence identically or differently, have the following meanings: 
         R 1  and R 2  denotes straight chain, alkyl having 1 to 25 C atoms or branched or cyclic alkyl having 3 to 25 C atoms, wherein one or more non-adjacent CH 2 -groups are optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, CR 0 ═CR 00 —, —C≡C—, 
       
       
         
           
           
               
               
           
         
       
       in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by F or Cl;
 A 1  and A 2  denote a group selected from the following formulae; 
 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         wherein the individual radicals, independently of each other and on each occurrence identically or differently, have the following meanings: 
         Z 1  and Z 2  denote —CH 2 CH 2 —, —CH═CH—, —CF 2 O—, —OCF 2 —, —CH 2 O—, —OCH 2 —, —CO—O—, —O—CO—, —C 2 F 4 —, —CF═CF—, —CH═CH—CH 2 O—, or a single bond; 
         L 1 , L 2 , L 3 , and L 4  
 denote F, Cl, OCF 3 , CF 3 , CH 3 , CH 2 F, or CHF 2 ; 
 
         Y denotes H, F, Cl, CF 3 , CHF 2 , or CH 3 ; 
         L c  denotes CH 3  or OCH 3 ; 
         a1 denotes 1 or 2; 
         a2 denotes 0 or 1; 
         optionally iii) one or more compounds of formula III: 
       
       
         
           
           
               
               
           
         
         in which 
         R 11  and R 12  
 each, independently of one another, denote H or an alkyl or alkoxy radical having 1 to 15 C atoms, where one or more CH 2  groups in these radicals may each be replaced, independently of one another, by 
 
       
       
         
           
           
               
               
           
         
       
       —C≡C—, —CF 2 O—, —OCF 2 —, —CH═CH—, by —O—, —CO—O—, or —O—CO— in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms are optionally replaced by halogen;
 A 3  on each occurrence, independently of one another, denotes
 a) 1,4-cyclohexenylene or 1,4-cyclohexylene radical, in which one or two non-adjacent CH 2  groups are optionally replaced by —O— or —S—, 
 b) a 1,4-phenylene radical, in which one or two CH groups are optionally replaced by N, or 
 c) a radical selected from the group consisting of spiro[3.3] heptane-2,6-diyl, 1,4-bicyclo[2.2.2] octylene, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, phenanthrene-2,7-diyl, and fluorene-2,7-diyl, 
 wherein the radicals a), b), and c) are optionally mono- or polysubstituted by halogen atoms; and 
 
 n denotes 0, 1, or 2; 
 optionally iv) one or more compounds of formula IV: 
 
       
         
           
           
               
               
           
         
         in which 
         R 41  denotes an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkenyl radical having 2 to 7 C atoms; and 
         R 42  denotes an unsubstituted alkyl radical having 1 to 7 C atoms, or an unsubstituted alkoxy radical having 1 to 6 C atoms, or an unsubstituted alkenyl radical having 2 to 7 C atoms; 
         optionally v) one or more compounds of formula V: 
       
       
         
           
           
               
               
           
         
         in which 
         R 51  and R 52  independently of one another, denote an unsubstituted alkyl radical
 having 1 to 7 C atoms, an unsubstituted alkenyl radical having 2 to 7 C atoms, or an unsubstituted alkoxy radical having 1 to 6 C atoms; 
 
       
       
         
           
           
               
               
           
         
       
       identically or differently, denote 
       
         
           
           
               
               
           
         
         Z 51 —, Z 52  each, independently of one another, denote —CH 2 —CH 2 —, —CH 2 —O—, —CH═CH—, —C≡C—, —COO—, or a single bond; and 
         n is 1 or 2; and/or 
         optionally vi) one or more additives selected from the group consisting of stabilizers, chiral dopants, polymerization initiators and self alignment additives, wherein the polymerizable compounds are polymerized between the substrates of the display by UV photopolymerization. 
       
     
     
         16 . The process for the production of an LC display according to  claim 15 , comprising the steps of providing the LC medium between the substrates of the display, and polymerizing the polymerizable compounds by irradiation with UV light, while a voltage is applied to the electrodes of the display. 
     
     
         17 . The process according to  claim 16 , wherein the UV light has a wavelength >360 nm. 
     
     
         18 . The process according to  claim 17 , wherein the UV light has a wavelength in the range from 360 to 380 nm. 
     
     
         19 . The process according to  claim 16 , wherein the irradiation with UV light is carried out using an UV-LED lamp. 
     
     
         20 . The LC display according to  claim 15 , wherein the compound of formula I comprises one or more compounds selected from subformulae I1-1 to I1-18: